Press roll for paper machines



C. R. GRIFFITH PRESS ROLL FOR PAPER MACHINES May 12, 1925. 1,537,439

Filed A Fil 13, 1922 e p --z Patented May 172, 1,925. Y

lutu'rlsov STATES CHARLES n. GRIFFITH,

1,537,439 'PATENT orricla.A

or PdErLANn, oEEeoN.

rEEss ROLL Eon PAPER MACHINES.

Application led April 13, 1922. Serial No.. 552,379.

To all whom it may concern.'

Be it known that LCH/ARLES GRIFFITH,

a citizen of theUnitedStates, and a resident of Portland, county ofMultnomah, and State of Oregon, have invented a certain new and usefulImprovement in Press Rolls for Paper Machines, of which the'following isa specification. l

My invention relatesto the press rolls of paper making machinery, thefunction of these rolls being, as well known,to express the surpluswater from paper stock.

These press rolls have been made of metal also of granite, but the metalroll was found unsatisfactory, because the paper` sheet had a tendencyto adhere to them, and then would revolve with the roll and break thesheet; and the granite roll was too expensive, and too easily broken.

It was also known that wooden rolls possessed the required porous orcellular surface, in other words, provided with minute cells in theircircumference,'and which cells hold air thus eectively prevented theadhesion of the sheet to the roll. But suitable wood is hard to get.Wood is generall found to vlack uniform texture, having so spots andknots, and in consequence requires frequent scrapings which tends torender the roll untrue, and requires-frequent regrinding, andconsequently is costly.

Another disadvantage of wood rolls is that only one degree of hardnesscan be obtained to. meet the requirements of diiferent kinds of paper. vTherefore the object of my Ainv'fenton is to make these press rolls ofsome substance which possesses the properties of hardness vsmoothnessand circumferential porosity;

i thus avoiding the adhering of the Asheet to the roll by 'rendering thesurface of ythe lati ter repellant. y

I attain my object b making my press rolls of vulcanized rub er which Irender porous or cellular at its circumference, by

mixing with the raw rubber composition i particles of cotton, or feltfibre, coarse saw 00 dust, (and the like, and then vulc'anizing therolls. -Press rolls sov produced require no wrapping, even when used forstraw paper. "Thesaid porous particles introduced in these vulcanizedrubber rolls are not con- 765 I sume'd by the heat of-vulcanization, butbeing themselves inherently porous', provide the desired porosity andthus a-ir cells in the circumference of the roll. Of .course onlythe-air cells in the circumference function, Y

but as the roll is -reground from time to time the interior pores or aircells are brought to the surface in turn.

The porosity of my'rubber composition carbonate of soda or ammonia,which substances are vaporized by the heat applied during vulcaniaation,leaving air, cells. The said porosity may also be obtained\ by mixingwith the rubber composition grass' 80 seed and like substances which areconsumed by the heat of the vulcanizing process.

Another feature obtained by my invention f is that a much lighterrollcan be made, be-

cause as there isno great amount of wearing o n the surface it need notlbe' made veryl thick, and requires'onlyenough material to give itrigidity. Furthermore, my improved press rolls can ybe made of anydesired degree of hardness required by the particular conditions underwhich. they are used.

The above describes the manners of'maklng my improved press roll, andthe article produced l have diagrammatically illustrated in theaccompanying drawings, in which:

\ Fig. l is a afragmentary view, partially sectional, of a rollembodying my `-i r1ven tion; p

Fig. 2 vshowsa pair' of press' rolls the A upper of which embodies myinvention and .is shown in cross section on aline corresponding to 2--2of'the roll shown in Fig.

'1; thisview also shows the sheet of pa er passing between .the pe rollsand earned to adjacent devices; v

Fig, 3 is a larger scaled fragmentary sec,

-tonofmy improved press roll diagrammatically illustratlng theappearance ofthe com-4 posltionssurface when produced by mixing with therubber composltion, any other marollsmay alsov f beA provided bymxingwith the raw rubber 75 provided with hollow stub shafts areplugge-d bymeans of plugs c. These i end caps are pressed into thehollow metal cylinder d, lwhich fits securely on the end caps, and isaxially alined with the same so that the whole assembly is trulyconcentric. Over the cylinder d is placed my rub- `ber compositioncovering e.

This rubber covering is made porous so as to provide the circumferentialrepelling air cells.

In Fig. 3 I haveindicated a porous surface in which the pores areindicated b the uneven black lines running across the tliickness of therubber composition material marked e. In Fig. 4 the sheet of paper f isshown in relation to the fibre composition surface e2. y'Ihe separateparts of Fig. 2

show the relations of the different rolls and conveyorslin a papermachine, `and of the sheet of paper passing therethrough. Referringfurther to Fig. 2, the sheet of paper f approaches the press conveyor g,and is considerably compressed between the bottom roll h and the toproll z' which embodies myl invention. Adhesion causes the paper to'cling to the periphery of the roll i to a point f', but then the aircells act to repel, in other .words break the adhesion and cause thepaper-.to become released, so that it may pass to the felt conveyor y',from which it passes to other parts i of the machinery.

My rubber press roll has a very tenacious and porous surface and meetsall the requirements of a top press roll. It furtherb, which rolls onthe wire P more successfully resists any appreciable wear, and will keepin good condition notwithstanding repeated re-grinding.

Iclaim:

1. A press roll, made of vulcanized rub ber having pores'providing aircells in the circumference thereof, to render the same repellent.

2. A press roll, made of vulcanized rubber composition having intermixedtherewith other material, rendering the mass more or less porous, andthereb providing air cells in the. circumference of the rollpto renderthe same repellent.

3. A press roll made of vulcanized rubber, having cellular particlesimbedded in its circumference, said particles constituting air cellsthereby rendering the roll repellent.

4. In a press roll for a paper.- machine, a

made of vulcanized rubber having cellular particles imbedded in itscircumference, said particles constituting air cells, thereby renderingthe roll repellent.

5. In a press roll for a paper machine, a4 hollow cylinder, stub shaftsfastened into the ends of said hollow cylinder, a covering fgr saidcylinder made of vulcanized rubber having cellular particles imbedded inits circumference, said particles constituting air cells, therebyrendering the roll repellent.

6. A top vpress roll for paper making machines having Aan active surfacecomosed of rubber and porous material.

hollow cylinder, a covering for said cylinder 7. A top press roll forpaper making machines having its -oute-r portion composed of rubber andporous fibrous material.4

8. A top press roll for paper making machines having its outer portionscomposed of rubber and cellulose.

9. A ytop press roll for paper making machines comprising a metal core;and a homogeneous coverlng consisting of rubber com- `poundedf withfinely ground cellulose, said covering being vulcanized to said core.

i oIARLEs R. GRIFFITH.

